I have some old pdf files in Kobo. In the new version of Kobo, when I add a PDF file, it shows its first page, which is very handy. In older version of Kobo, this was not the case, so all my old documents (about 100 of them) show up as just the letter "PDF". Is there a way to make sure Kobo shows me the visual for each of those older PDFs? Thanks.